Acrobat Reader & Acrobat Standard

I can not get either to open. I have uninstalled & reinstalled to no avail. TIA

My OS is Windows XP Professional; 120 GB HD, with
95 GB free; 2.4 GHZ Pentium 4; 2.39 GHz 512 MB ram. Hope this can help answer my problem. The Reader is version 6.0.2 (updated); Acrobat Standard is 6.0.
TIA